1. Field of the Invention
The present invention relates to an image pickup apparatus for converting an image signal (which represents an image picked up using a solid-state image pickup device) into a digital video signal in one of a plurality of modes, and to an image pickup recording/reproducing apparatus for recording/reproducing an output from the image pickup apparatus.
2. Description of the Related Art
In accordance with recent progress in digital signal processing techniques, many image pickup recording/reproducing apparatuses, in which an image signal representing a picked-up image is subjected to digital processing and the resultant signal is recorded in/reproduced from a tape or a disk device as a digital video signal, have been proposed.
In these methods, an output signal from an image pickup device, such as a CCD (charge-coupled device) or the like, is subjected to an analog-to-digital conversion by an A/D (analog-to-digital) converter, and a resultant signal is processed by a digital-signal processing circuit to obtain a digital video signal, which is converted into recording data by a digital recording processing circuit, and the recording data is recorded on a tape or a disk device. A digital reproducing processing circuit forms a digital video signal from an output of the tape or the disk device, and outputs the formed signal to an external apparatus as a reproduced digital video signal.
However, the above-described conventional approach has the following problems.
That is, a reproduced digital video signal, in the conventional approach, is supplied to various kinds of external apparatuses. For example, after performing D/A (digital-to-analog) conversion, the obtained signal may be supplied to an ordinary television monitor, a still-image input apparatus or a moving-image input apparatus of a personal computer, a color printer, a video conference system, or the like.
These apparatuses may be grossly classified into apparatuses which deal with still-image data (still-image input apparatuses such as personal computers and color printers in the above-described examples), and apparatuses which deal with moving-image data (such as television monitors, video conference systems, and moving-image input apparatuses of personal computers in the above-described examples). In apparatuses which deal with still-image data, data having a number of pixels per frame as large as possible is required. Among apparatuses which deal with moving-image data, for example, NTSC-system television monitors deal with 2:1 interlaced images of 60 fields/sec and 240 lines in the vertical direction, and some other apparatuses deal with non-interlaced images of 30 frames/sec and 240 lines in the vertical direction although these values depend on the system, and the processing capability of a CPU used in the apparatus.
Recording/reproducing units used in the above-described conventional approach can record/reproduce only interlaced images of 60 fields/sec and 240 lines in the vertical direction. Hence, when a signal from such a unit is input to an apparatus which deals with a still image, particularly, resolution in the vertical direction is low, so that it is impossible to display or print an image in a large size, or only an image having a low picture quality is displayed or printed.
When intending to improve resolution by synthesizing interlaced images for two fields, if an object is moving, a moving portion becomes indented or blurred.
The present invention has been made in consideration of the above-described problems.
It is an object of the present invention to provide an image pickup apparatus which can obtain high-picture-quality still images and moving images capable of being interlaced, and an image pickup recording/reproducing apparatus which uses such a device.
In order to achieve the above-described object, according to one aspect of the present invention, an image pickup apparatus is configured according to the following items (1) -(5), (7) and (8), and an image pickup recording/reproducing apparatus is configured according to the following item (6).
(1) An image pickup apparatus for converting a signal representing an image picked up using an image pickup device (for example, a progressive-scanning-type device) for sequentially reading out outputs of respective pixels without adding the outputs into a digital signal, performing predetermined processing for the digital signal, and outputting a resultant signal includes an operational-mode switch to be set by an operator, a driving circuit capable of setting a horizontal transfer frequency for the image pickup device to a first frequency or to second frequency different from the first frequency, a memory block for delaying an output of the image pickup device by a predetermined number of lines, and control means for causing, when a first operational mode has been set by the operational-mode switch, the driving circuit to drive the image pickup device with a horizontal transfer frequency equal to the first frequency to cause a writing operation and a reading operation with respect to the memory block with the same frequency, and for causing, when a second operational mode has been set by the operational-mode switch, the driving circuit to drive the image pickup device with a horizontal transfer frequency equal to the second frequency to cause a writing operation and a reading operation with respect to the memory block with the second frequency and the first frequency, respectively.
(2) An image pickup apparatus described in item (1), wherein, when the second operational mode has been set, signals output from the memory block are interlaced.
(3) An image pickup apparatus described in item (1), wherein the memory block includes output terminals for out-putting a plurality of signals shifted by one horizontal period from each other.
(4) An image pickup apparatus described in item (1), further including signal processing means for performing signal processing using line correlation.
(5) An image pickup apparatus described in item (4), wherein the signal processing means performs signal processing using a vertical filter.
(6) An image pickup recording/reproducing apparatus, including an image pickup apparatus described in any one of items (1) through (5), for recording/reproducing an output of the image pickup device.
(7) An image pickup apparatus described in item (1), wherein the second frequency is twice the first frequency.
(8) An image pickup apparatus described in item (1). wherein the image pickup device is a progressive-scanning-type image pickup element.
The foregoing and other objects, advantages and features of the present invention will become more apparent from the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings.
According to another aspect of the present invention an image pickup apparatus includes image pickup means, a mode, switch for switching between a movie mode and a still mode, and drive means for driving the image pickup means in a first frequency in the movie mode and in a second, lower frequency in the still mode.
According to another aspect of the present invention, an image pickup apparatus which can operate in a still image mode and in a moving-image mode, includes a solid-state image pickup device for picking up an image and outputting electrical signals corresponding thereto and a line-memory block for storing lines of electrically signals output from said solid state image pickup device. Control means are provided for driving said line-block memory at a first frequency in the still image mode and at a second, different frequency in the moving image mode.